What is the maximum email attachment size?

Limits vary by provider: Gmail allows up to 25 MB, Outlook up to 20 MB, and Yahoo Mail up to 25 MB. Many corporate email servers have stricter limits of 10 MB or less.

Which setting should I use for emailing a PDF?

The Medium quality setting usually reduces file size by 60–80% while keeping text and images clearly readable. For very large PDFs or strict size limits, try the Low setting.

Will the compressed PDF look different to the recipient?

Lossless compression is invisible. Medium quality is typically indistinguishable at normal reading zoom. Low quality may show mild JPEG artefacts on high-resolution images or very small text.

Can I use this for scanned documents?

Yes. Scanned PDFs often compress very well with the Medium or Low setting because each page is already an image. The reduction can be 70–90% for typical scanned documents.

Is my PDF sent anywhere?

All processing runs in your browser tab using pdf-lib and the Canvas API. Our servers are not involved at any point.

Compress PDF for Email

Most email providers limit attachments to 10–25 MB. If your PDF is too large to send, use the Medium quality setting for a significant size reduction while keeping the document legible. All processing happens locally in your browser.

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How it works

When the goal is a clean attachment, Medium quality usually does the trick. pdfjs-dist renders each page to a Canvas, the canvas is exported as a moderately compressed JPEG, and pdf-lib rebuilds the document with those images. The resulting PDF is small enough for the major mail providers' attachment limits while staying readable at normal zoom. Lossless mode is also available when you want the original text layer preserved.

Processing runs in your browser

Compression runs in your browser tab. pdf-lib and PDF.js shrink the PDF inside the page, and the result lands in your downloads ready to attach. You can check this yourselfin your browser's DevTools Network tab.

Related operations

To stitch multiple PDFs into one before compressing, try merge PDF. For pulling out a subset of pages, use split PDF. To extract pages as standalone images, see PDF to image.

Frequently asked questions

What is the maximum email attachment size?: Limits vary by provider: Gmail allows up to 25 MB, Outlook up to 20 MB, and Yahoo Mail up to 25 MB. Many corporate email servers have stricter limits of 10 MB or less.
Which setting should I use for emailing a PDF?: The Medium quality setting usually reduces file size by 60–80% while keeping text and images clearly readable. For very large PDFs or strict size limits, try the Low setting.
Will the compressed PDF look different to the recipient?: Lossless compression is invisible. Medium quality is typically indistinguishable at normal reading zoom. Low quality may show mild JPEG artefacts on high-resolution images or very small text.
Can I use this for scanned documents?: Yes. Scanned PDFs often compress very well with the Medium or Low setting because each page is already an image. The reduction can be 70–90% for typical scanned documents.
Is my PDF sent anywhere?: All processing runs in your browser tab using pdf-lib and the Canvas API. Our servers are not involved at any point.

Compress PDF for Email

How it works

Processing runs in your browser

Related operations

Frequently asked questions

Related tools